Mammography and tomosynthesis for breast cancer screening
In most countries, organized screening strategies have been put in place to detect cases of breast cancer as early as possible, in order to optimize treatment and reduce mortality.
Breast cancer is the 2nd most common cancer in France in women (source : HAS - Performance de la mammographie par tomosynthèse dans le dépistage organisé du cancer du sein) it even represents 16% of all female cancers in the world (source : WHO - Breast cancer: prevention and control) which makes it the most common cancer in women. This applies to both developed and developing countries, there is an increase in its incidence linked to factors such as increased life expectancy or environmental factors such as lifestyles. It is estimated that more than 500,000 deaths are caused by this cancer worldwide. In France, nearly 60,000 new cases are detected each year and more than 12,000 deaths are recorded.
In most countries, organized screening strategies have been put in place to detect cases of breast cancer as early as possible, in order to optimize treatment and thus reduce mortality. These strategies are essentially based on mammography. In France, the examination includes a mammogram (two images per breast, face and oblique) and a clinical examination of the breasts. The organized screening program benefits from supervised double reading: participating radiologists, known as “first readers”, must perform at least 500 mammograms per year. Radiologists providing the second reading must, for their part, commit to reading at least 1,500 mammograms per year as part of this second reading activity. Thus, if no abnormality is detected, the mammogram will still be systematically reread by a second expert radiologist. When an anomaly is detected, the first reader radiologist immediately carries out a diagnostic workup to shorten the time for possible treatment and avoid an agonizing wait for the patient.
The value of tomosynthesis in breast cancer screening
Tomosynthesis corresponds to the performance of a mammographic exploration, using a full-field digital mammography machine, allowing volume acquisition of the breast (3D). It is based on the limited rotation of an X-ray tube, around a point close to the detector, which allows the acquisition of a series of 2-dimensional (2D) mammographic images of a compressed breast, under different angles; each of these exposures is carried out at a reduced dose and, from the various 2D projections acquired, the breast volume (in 3D) is then reconstructed using a complex algorithm. Breast volume can be visualized by scanning all the reconstructed thick sectional images (typically 1mm) in planes parallel to the detector. Breast compression is similar to a conventional mammography. The compression time is however longer (5 to 6 seconds). If the breast compression were less important, the dose delivered should, be higher and the quality of the image would be lower.
The main advantage of tomosynthesis lies in the fact that it provides reading comfort as well as better precision in the characterization of anomalies and a reduction in the risks of misinterpretation linked to the superposition of images in the context of a “classic” mammography (constructed image effect). In an individual setting, we can see the development of the practice of breast cancer screening by tomosynthesis, but to date in France, the organized screening program does not integrate this technique, its interest is being evaluated and certain studies highlight its performance. But among the drawbacks, we find the X-ray dose delivered much higher under certain conditions of use compare to a 2D mammogram. To date, very few robust studies exist on a comparison of performance in screening between simple mammography and tomosynthesis. However, most of the studies identified are consistent and indicate that the clinical performance of tomosynthesis combined with mammography is superior to a standard mammography both in terms of increased detection of breast cancer and reduction of recall rate.
Myrian 2.8 has chosen to integrate tomosynthesis
The new version 2.8 of Myrian integrates tomosynthesis in its XP-Mammo solution dedicated to mammographic imaging. This new very powerful tool allows the reading of standard mammographic images, tomosynthesis, as well as the comparison with previous examinations. In addition, and without changing the interface, it is also possible, via this dedicated mammography platform, to view additional ultrasound examinations and MRI sequences. This improves radiologist reading comfort and analyzing to optimize the diagnosis for the patient.
More broadly, Intrasense has developed a complete range of clinical applications dedicated to breast imaging. With our breast MRI application XP-Breast, allowing the complete analysis of breast MRI exams and now a new clinical application dedicated to mammography.